mic/speaker problem

Hello I'm using suse 8.2 and 9. In both I have the problem that the microphone is always listening to the speakers, even when I have earphones and a separate microphone. Looking at the sound configuration through gnomemeeting the mic and the speakers are in /dev/dsp0 I'm guessing that they should be different devices, but I have no idea how to do that. Any suggestion? Thanks in advance Juan C. Gallardo